Sharks: The Animal Answer Guide

8 Sharks and Humans

157 Chapter 8 Sharks and Humans Do sharks make good pets? This question actually has two parts: (1) Can sharks be kept in home aquariums? and (2) Do they make good pets? First off, note that the freshwater aquarium fishes called “sharks” are actually minnows, not sharks. Examples are Bala, Redtail, Variegated, Rainbow, and Redfin. They’re lovely, easy to keep, small, and relatively cheap. They get their sharky names because of their body shape and a large, shark-like dorsal fin. But don’t be fooled. A number of actual sharks can be kept in home aquariums, although most eventually outgrow all but the largest living room tanks. Epaulette Sharks, Zebra Sharks, Bamboo and Brown-spotted Cat Sharks, Port Jackson Sharks, and Nurse Sharks are among the species offered for sale from aquarium suppliers, but almost all grow to be more than 1 m (3 ft) in length, are expensive, have stringent water quality requirements, and are mostly active at night (so not very interesting). For example, ■ Epaulette Sharks ($350) are relatively sluggish bottom dwellers. They are attractive because they move across the bottom by “walking” on their pectoral and pelvic fins (but usually at night; by day, they hide in crevices). They will breed in captivity, but only in an aquarium larger than 510 L (135 gal). Advice on a website that sells them: “Care Level: Expert Only!!! Behavior: Aggressive. Minimum Tank Size: 180 Gallon .” ■ Zebra Sharks ($150), which are cute and colorful as pups, carry similar warnings: “Expert Only!!! Aggressive. Minimum Tank Size: 100 Gallon.” 158 Sharks: The Animal Answer Guide ■ Bamboo Sharks ($100): “Temperatures between 72 and 78 degrees Fahrenheit , pH of 8.1 or 8.4, specific gravity of 1.020 to 1.025. . . . Strong shark can easy dislodge unstable rock formations and corals. . . . All items in the tank should be stable.” ■ Port Jackson Sharks ($750): “Have a spine at the front of both dorsal fins that can cause injury . . . is a difficult fish to acclimate and may not eat. . . . Once eating well, it will eat virtually any crustacean or mollusk in the aquarium and will also prey upon any sleeping fish small enough for it to eat whole.” ■ Nurse sharks ($300): “Can reach a length of 4.3 m (14 ft) and a weight of 330 lbs (150 kg).” Let the buyer beware. In addition to outgrowing their confined quarters, all elasmobranchs are carnivores, and most are predatory, which guarantees frustration if you want to keep more than one fish in a tank. Any shark can inflict a painful, damaging bite when handled. Some saltwater rays are sold in the aquarium trade, but most grow too large for a home hobbyist. We have seen electric torpedo rays (Torpedinidae ) for sale for as little as $80, but we can’t imagine a more unsuitable and dangerous aquarium species. Freshwater stingrays (Potamotrygonidae) from the Amazon River basin are sold in pet stores and online. They have an advantage over sharks because they are freshwater animals and generally easier to keep than saltwater fishes. Some are bred in captivity, which is better than removing individuals from the wild. But they are expensive; a typical 8-inch-diameter (20-cm) Motoro Stingray sells for $200 to $300 or more (4-in stingrays may cost “only” $70)! And all but a couple of species grow to over 3 feet across, which makes them unsuitable for most home aquariums. Add to these problems the complication that it is illegal to sell or own a freshwater stingray in many states. As you can discover by reading posts on aquarium blogs, their care is complicated, their water quality requirements are exacting, and they go from apparently healthy to dead in a matter of hours (or shorter). And, oh yes, they do have that lethal barb, which gets fouled up in any kind of net if you have to move one for any reason , and then it can stab you as you try to untangle it. Keeping freshwater fishes is relatively easy, but marine fishes—which means 99% of elasmobranchs—are another matter altogether. Marine fishes are more sensitive to water quality, temperature, food type, and disease than most freshwater fishes. Marine species are difficult to breed in captivity and thus must be captured in the wild, often with methods that destroy habitats and other animals. A responsible aquarist can avoid many problems by purchasing fishes that are on the American Marinelife Dealers Association’s Ecolist of species that are easily maintained (see...